Comparison of Vibroseis and explosive source methods for deep crustal seismic reflection profiling in the Basin and Range province
T.M. Brocher, P. E. Hart
1991, Journal of Geophysical Research (96) 18197-18213
Direct comparison of low-fold, high-energy explosive and high-fold, lower-energy Vibroseis methods for acquiring deep crustal seismic reflection data in the Basin and Range Province suggests that the high-fold common midpoint (CMP) method there does not provide the best possible image of lower crustal structure. During...
Coprecipitation mechanisms and products in manganese oxidation in the presence of cadmium
J.D. Hem, Carol J. Lind
1991, Geochimica et Cosmochimica Acta (55) 2435-2451
Manganese oxidation products were precipitated in an aerated open-aqueous system where a continuous influx of mixed Mn2+ and Cd2+ solution was supplied and pH was maintained with an automated pH-stat adding dilute NaOH. X-ray diffraction and electron diffraction identified the solids produced as mixtures of Cd2Mn34+O8, Mn2+2Mn4+3O8, MnO2 (ramsdellite), and CdCO3. Mean oxidation...
Large-scale variation in lithospheric structure along and across the Kenya rift
C. Prodehl, J. Mechie, W. Kaminski, K. Fuchs, C. Grosse, H. Hoffmann, R. Stangl, R. Stellrecht, M.A. Khan, Peter K.H. Maguire, W. Kirk, Gordon R. Keller, A. Githui, M. Baker, Walter D. Mooney, E. Criley, J. Luetgert, B. Jacob, H. Thybo, M. Demartin, S. Scarascia, A. Hirn, J. R. Bowman, I. Nyambok, S. Gaciri, J. Patel, E. Dindi, D.H. Griffiths, R.F. King, A. E. Mussett, L.W. Braile, G. Thompson, K. Olsen, S. Harder, R. Vees, D. Gajewski, A. Schulte, J. Obel, F. Mwango, J. Mukinya, D. Riaroh
1991, Nature (354) 223-227
The Kenya rift is one of the classic examples of a continental rift zone: models for its evolution range from extension of the lithosphere by pure shear1, through extension by simple shear2, to diapiric upwelling of an asthenolith3. Following a pilot study in 19854, the present work involved the shooting...
The use of mineralogic techniques as relative age indicators for weathering profiles on the Atlantic Coastal Plain, USA
D. R. Soller, J. P. Owens
1991, Geoderma (51) 111-131
Textural, geochemical, and mineralogic study of soils and weathering profiles has led to the practice of applying varioys weathering parameters as relative age indicators. In our studies examined the entire thickness of weathered sediment (i.e., the weathering profile) for evidence of weathering-induced changes in both sand- and clay-sized mineralogy, and...
Implications of low-temperature cooling history on a transect across the Colorado Plateau-Basin and Range boundary, west central Arizona
B. Bryant, C. W. Naeser, J.E. Fryxell
1991, Journal of Geophysical Research (96) 12375-12388
Fission track ages of apatite and zircon from metamorphic, plutonic, and sedimentary rocks along a 80-km transect across the Colorado Plateau-Basin and Range boundary in west central Arizona show differences in the low-temperature cooling histories between the provinces. The transect extends from Cypress Mountain in...
Geochemistry of a Tertiary sedimentary phosphate deposit: Baja California Sur, Mexico
D.Z. Piper
1991, Chemical Geology (92) 283-316
The San Gregorio Formation in Baja California Sur, a phosphate-enriched sedimentary unit of late Oligocene to early Miocene age, has been analyzed in two areas (La Purisima and San Hilario) for its chemical composition (major oxides, Cu, Cd, Cr, Co, V, and rare-earth elements - REE) and isotopic composition (??18O...
S-layer positive motile aeromonads isolated from channel catfish
L.A. Ford
1991, Journal of Wildlife Diseases (27) 557-561
Motile aeromonads are ubiquitous aquatic bacteria that can cause motile aeromonad septicemia (MAS), a disease which affects channel catfish and can produce significant economic loss. Motile aeromonads isolated from commercially-raised channel catfish were screened for production of S-layer protein in order to evaluate...
A comparison of Sr-Nd-Pb isotopes in young and old continental lithospheric mantle: Patagonia and eastern China
R. E. Zartman, K. Futa, Z. C. Peng
1991, Australian Journal of Earth Sciences (38) 545-557
It is commonly accepted that beneath the continental crust lies a keel of lithospheric mantle, which extends 50–200 kilometres downward to a transition zone into the asthenosphere. The chemical and physical properties of this reservoir are best known through studies of the basalts and xenoliths that provide samples of the...
Fossil and active fumaroles in the 1912 eruptive deposits, Valley of ten thousand smokes, Alaska
T. E. C. Keith
1991, Journal of Volcanology and Geothermal Research (45) 227-254
Fumaroles in the ash-flow sheet emplaced during the 1912 eruption of Novarupta were intensely active throughout the Valley of Ten Thousand Smokes (VTTS) when first studied in 1917. Fumarole temperatures recorded in 1919 were as hot as 645??C. Influx of surface waters into the hot ash-flow sheet provided the fluid...
Isotopic and chemical constraints on the petrogenesis of Blackburn Hills volcanic field, western Alaska
E. J. Moll-Stalcup, Joseph G. Arth
1991, Geochimica et Cosmochimica Acta (55) 3753-3776
The Blackburn Hills volcanic field is one of several Late Cretaceous and early Tertiary (75–50 Ma) volcanic fields in western Alaska that comprise a vast magmatic province extending from the Arctic Circle to Bristol Bay. It consists of andesite flows, rhyolite domes, a central granodiorite to quartz monzonite pluton, and...
Examination of micrinite concentrates from the Cannel City coal bed of eastern Kentucky: Proposed mechanism of formation
D.N. Taulbee, J.C. Hower, S.F. Greb
1991, Organic Geochemistry (17) 557-565
A high volatile B, micrinite-rich bituminous coal from Morgan County, Kentucky, was crushed and screened to −100 mesh, demineralized and subjected to density gradient centrifugation (DGC). In an initial density separation, micrinite concentration was increased from 52 vol% in the demineralized coal to a maximum of 67% in the 1.25–1.26...
Surface features of central North America: a synoptic view from computer graphics
R.J. Pike
1991, GSA Today (1) 1-251
A digital shaded-relief image of the 48 contiguous United States shows the details of large- and small-scale landforms, including several linear trends. The features faithfully reflect tectonism, continental glaciation, fluvial activity, volcanism, and other surface-shaping events and processes. The new map not only depicts topography accurately and in its true...
Real-time Seismic Amplitude Measurement (RSAM): a volcano monitoring and prediction tool
E.T. Endo, T. Murray
1991, Bulletin of Volcanology (53) 533-545
Seismicity is one of the most commonly monitored phenomena used to determine the state of a volcano and for the prediction of volcanic eruptions. Although several real-time earthquake-detection and data acquisition systems exist, few continuously measure seismic amplitude in circumstances where individual events are difficult to recognize or where volcanic...
Evolution of deep structure along the trans-Alaska crustal transect, Chugach Mountains and Copper River Basin, southern Alaska
G. S. Fuis, George Plafker
1991, Journal of Geophysical Research (96) 4229-4253
One of the most important results of the Trans-Alaska Crustal Transect investigations is the discovery that more than one third of the North American plate in southern Alaska (Chugach Mountains and Copper River basin) consists of tectonically underplated oceanic lithosphere. In southern Alaska, exposed accreted...
An exact solution of solute transport by one-dimensional random velocity fields
V.D. Cvetkovic, G. Dagan, A.M. Shapiro
1991, Stochastic Hydrology and Hydraulics (5) 45-54
The problem of one-dimensional transport of passive solute by a random steady velocity field is investigated. This problem is representative of solute movement in porous media, for example, in vertical flow through a horizontally stratified formation of variable porosity with a constant flux at the soil surface. Relating moments of...
Scale, variable density, and conservation planning for mammalian carnivores
C. Schonewald-Cox, R. Azari, S. Blume
1991, Conservation Biology (5) 491-495
Many mammalian carnivores are in local or global decline. To slow this process, continued planning to protect these species is warranted, Still, the data bases that we have at our disposal do not adequately document population requirements for space at scales appropriate for conservation planning. To illustrate this problem, we...
Origin of xenoliths in the trachyte at Puu Waawaa, Hualalai Volcano, Hawaii
David A. Clague, Wendy A. Bohrson
1991, Contributions to Mineralogy and Petrology (108) 439-452
Rare dunite and 2-pyroxene gabbro xenoliths occur in banded trachyte at Puu Waawaa on Hualalai Volcano, Hawaii. Mineral compositions suggest that these xenoliths formed as cumulates of tholeiitic basalt at shallow depth in a subcaldera magma reservoir. Subsequently, the minerals in the xenoliths underwent subsolidus reequilibration that particularly affected chromite...
Regional hydrogeological screening characteristics used for siting near-surface waste-disposal facilities in Oklahoma, U.S.A.
K.S. Johnson
1991, Environmental Geology and Water Sciences (17) 3-7
The Oklahoma Geological Survey has developed several maps and reports for preliminary screening of the state of Oklahoma to identify areas that are generally acceptable or unacceptable for disposal of a wide variety of waste materials. These maps and reports focus on the geologic and hydrogeologic parameters that must be...
The Reaction Titanite+Kyanite=Anorthite+Rutile and Titanite-Rutile Barometry in Eclogites
C.F. Manning, S.R. Bohlen
1991, Contributions to Mineralogy and Petrology (109) 1-9
Titanite and rutile are a common mineral pair in eclogites, and many equilibria involving these phases are potentially useful in estimating pressures of metamorphism. We have reversed one such reaction, {Mathematical expression} using a piston-cylinder apparatus. Titanite+kyanite is the high-pressure assemblage and our results locate the equilibrium between 15.5 15.9,...
In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests
R. L. Smith, B.L. Howes, S. P. Garabedian
1991, Applied and Environmental Microbiology (57) 1997-2004
Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate...
Partitioning and bioavailability of mercury in an experimentally acidified Wisconsin lake
James G. Wiener, William F. Fitzgerald, Carl J. Watras, Ronald G. Rada
1990, Environmental Toxicology and Chemistry (9) 909-918
We studied the partitioning of mercury (Hg) among air, water, sediments and fish at Little Rock Lake, a clear water seepage lake in north-central Wisconsin. The lake was divided with a sea curtain into two basins, one acidified with sulfuric acid to pH 5.6 for two years and the other...
Annual variation in foraging ecology of prothonotary warblers during the breeding season
L. J. Petit, D. R. Petit, K.E. Petit, W. James Fleming
1990, The Auk (107) 146-152
We studied foraging ecology of Prothonotary Warblers (Protonotaria citrea) along the Tennessee River in west-central Tennessee during the breeding seasons of 1984-1987. We analyzed seven foraging variables to determine if this population exhibited annual variation in foraging behavior. Based on nearly 3,000 foraging maneuvers, most variables showed significant interyear variation...
Lead hazards within the range of the California condor
O. H. Pattee, P.H. Bloom, J. M. Scott, M. R. Smith
1990, Condor (92) 931-937
The prevalence of lead in Golden Eagles (Aquila chrysaetos) occurring within the recent historical range of the California Condor (Gymnogyps californianus) was determined by analyzing blood samples from 162 Golden Eagles captured between June 1985 and December 1986 at three sites. We found no significant differences between sex and age...
Renesting by American woodcocks (Scolopax minor) in Maine
D.G. McAuley, J. R. Longcore, G.F. Sepik
1990, The Auk (107) 407-410
The American Woodcock (Scolopax minor) is one of the earliest ground-nesting birds in the northeastern United States. In Maine, nesting begins in early April when temperatures can drop below freezing and significant snowfall can accumulate. Nests are usually in open woods, where eggs are laid on the ground in...
Comparison of breaking strength and shell thickness as evaluators of white-faced ibis eggshell quality
Charles J. Henny, J.K. Bennett
1990, Environmental Toxicology and Chemistry (9) 797-805
Data from a 1986 field study of white-faced ibis (Plegadis chihi) nesting at Carson Lake, Nevada, were used to compare the utility of eggshell strength measurement and eggshell thickness as indicators of eggshell quality. The ibis population had a history of reproductive failure correlated with elevated egg concentrations of p, p'-DDE,...
